Marching Toward 1-s Movie Downloads

Researchers at IBM’s T.J. Watson Research Center in Yorktown Heights, N.Y., have developed a novel optical transceiver that can move data at a rate of 160 Gb/s — fast enough to enable consumers to download a high-definition movie in about one second.

The device uses 16 vertical-cavity surface-emitting lasers, each of which modulates a 985-nm continuous-wave laser beam at >10 GHz, which the company says is a record for individual devices in a transceiver. The device’s 16-channel receiver-amplifier block matches the 160 Gb/s threshold. Tests indicated that each channel likely can contribute more than 10 Gb/s, and degradation resulting from crosstalk was <1.0 dB in the worst case. The optical channels can be fibers or optical waveguides printed on a circuit board. The chip consumes 15.6 mW Gb^–1 s^–1 — or 2.5 W total — and has an area efficiency of 9.4 Gb s^–1 mm^–2 per optical link.

To construct the device, the investigators built an optical transceiver using CMOS technology, then coupled it with optical components composed of indium phosphide and gallium arsenide. The entire chip is 3.25 × 5.25 mm. The company announced the technology at the OFC/NFOEC Conference and Exposition in Anaheim, Calif., in March.

The company is developing the transceiver as part of Chip to Chip Optical Interconnect, a program sponsored by the Defense Advanced Research Projects Agency that is designed to speed up communications between supercomputers.